Solid-state imaging device, and electronic apparatus

ABSTRACT

The present technology relates to a solid-state imaging device and an electronic apparatus which make it possible to improve pixel property. Provided is a solid-state imaging device, including a first electrode formed on a semiconductor layer, a photoelectric conversion layer formed on the first electrode, a second electrode formed on the photoelectric conversion layer, and a third electrode disposed between the first electrode and an adjacent first electrode, and electrically insulated. A voltage of the third electrode is controlled to a voltage corresponding to a detection result which contributes to control of discharge of charges or assist for transfer of charges. The present technology can be applied to, for example, a CMOS image sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International PatentApplication No. PCT/JP2018/012713 filed on Mar. 28, 2018, which claimspriority benefit of Japanese Patent Application No. JP 2017-078182 filedin the Japan Patent Office on Apr. 11, 2017. Each of theabove-referenced applications is hereby incorporated herein by referencein its entirety.

TECHNICAL FIELD

The present technology relates to a solid-state imaging device and anelectronic apparatus, particularly to a solid-state imaging device andan electronic apparatus with which pixel property can be improved.

BACKGROUND ART

In relation to a solid-state imaging device such as a CMOS(Complementary Metal Oxide Semiconductor) image sensor, there is atechnology disclosed by which a shield electrode is disposed forseparation between lower electrodes of a pixel (see PTL 1, for example).

In the solid-state imaging device, disposing a shield electrode makes itpossible to prevent coupling between pixels, improve a readout speed ofelectric charges by applying a lateral electric field, and dischargeunnecessary charges which have not been read out.

CITATION LIST Patent Literature

[PTL 1]

PCT Patent Publication No. WO2013/001809

SUMMARY Technical Problem

Incidentally, an inadequate voltage difference between a lower electrodeand a shield electrode deteriorates a pixel property in some cases, anda technology for suppressing such a deterioration of the pixel propertyis required.

The present technology is made in view of such a situation, and makes itpossible to improve the pixel property.

Solution to Problem

The solid-state imaging device according to a first aspect of thepresent technology is a solid-state imaging device including a firstelectrode formed on a semiconductor layer, a photoelectric conversionlayer formed on the first electrode, a second electrode formed on thephotoelectric conversion layer, and a third electrode disposed betweenthe first electrode and an adjacent first electrode, and electricallyinsulated. A voltage of the third electrode is controlled to a voltagecorresponding to a detection result which can contribute to control ofdischarge of charges or assist for transfer of charges.

In the solid-state imaging device according to the first aspect of thepresent technology, the voltage of the third electrode disposed betweenthe adjacent first electrodes formed on the semiconductor layer andelectrically insulated is controlled to a voltage corresponding to adetection result which can contribute to control of discharge of chargesor assist for transfer of charges.

The electronic apparatus according to a second aspect of the presenttechnology is an electronic apparatus mounted with a solid-state imagingdevice, the solid-state imaging device including a first electrodeformed on a semiconductor layer, a photoelectric conversion layer formedon the first electrode, a second electrode formed on the photoelectricconversion layer, and a third electrode disposed between the firstelectrode and an adjacent first electrode, and electrically insulated. Avoltage of the third electrode is controlled to a voltage correspondingto a detection result which can contribute to control of discharge ofcharges or assist for transfer of charges.

In the electronic apparatus according to the second aspect of thepresent technology, the voltage of the third electrode disposed betweenthe adjacent first electrodes formed on the semiconductor layer andelectrically insulated is controlled to a voltage corresponding to adetection result which can contribute to control of discharge of chargesor assist for transfer of charges.

The solid-state imaging device according to the first aspect of thepresent technology or the electronic apparatus according to the secondaspect of the present technology may be an independent device or aninternal block constituting one device.

Advantageous Effect of Invention

According to the first and second aspects of the present technology, thepixel property can be improved.

Note that the effect described herein is not necessarily limited, andmay be any effect described in the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram depicting a configuration example of an embodimentof a solid-state imaging device to which the present technology isapplied.

FIG. 2 is a sectional view depicting a structure of a general pixel.

FIG. 3 is a sectional view depicting a structure of a general pixel.

FIG. 4 is a sectional view depicting a structure of a general pixel.

FIG. 5 is a sectional view depicting a structure of a pixel according tothe present technology.

FIG. 6 is a plan view depicting the structure of the pixel according tothe present technology.

FIG. 7 is a sectional view depicting a structure of a pixel according toa first embodiment.

FIG. 8 is a sectional view depicting the structure of the pixelaccording to the first embodiment.

FIG. 9 is a sectional view depicting the structure of the pixelaccording to the first embodiment.

FIGS. 10A and 10B are diagrams illustrating a first control methodaccording to the first embodiment.

FIGS. 11A and 11B are diagrams illustrating the first control methodaccording to the first embodiment.

FIG. 12 is a diagram illustrating the first control method according tothe first embodiment.

FIGS. 13A, 13B, 13C, and 13D are diagrams illustrating a second controlmethod according to the first embodiment.

FIG. 14 is a diagram illustrating a third control method according tothe first embodiment.

FIG. 15 is a diagram illustrating a fourth control method according tothe first embodiment.

FIG. 16 is a diagram illustrating a fifth control method according tothe first embodiment.

FIG. 17 is a sectional view depicting a structure of a pixel accordingto a second embodiment.

FIG. 18 is a plan view depicting the structure of the pixel according tothe second embodiment.

FIG. 19 is a plan view depicting a structure of a pixel according to athird embodiment.

FIG. 20 is a plan view depicting the structure of the pixel according tothe third embodiment.

FIG. 21 is a plan view depicting the structure of the pixel according tothe third embodiment.

FIG. 22 is a plan view depicting a structure of a pixel according to afourth embodiment.

FIG. 23 is a diagram representing an example of a voltage set for ashield electrode.

FIG. 24 a block diagram depicting a configuration example of anelectronic apparatus having the solid-state imaging device to which thepresent technology is applied.

FIG. 25 is a diagram depicting a usage example of the solid-stateimaging device to which the present technology is applied.

FIG. 26 is a block diagram depicting an example of schematicconfiguration of a vehicle control system.

FIG. 27 is a diagram of assistance in explaining an example ofinstallation positions of an outside-vehicle information detectingsection and an imaging section.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present technology will be explainedwith reference to the figures. Note that the explanation follows thefollowing order.

-   1. Configuration of Solid-State Imaging Device-   2. Overview of the Present Technology-   3. First Embodiment: Control of Setting Optimum Voltage for Shield    Electrode-   4. Second Embodiment: Structure of Divided Lower Electrode-   5. Third Embodiment: Arrangement Variation of Shield Electrode-   6. Fourth Embodiment: Another Arrangement Variation of Shield    Electrode-   7. Modification Example-   8. Configuration of Electronic Apparatus-   9. Usage Example of Solid-State Imaging Device-   10. Application Example to Mobile Bodies    <1. Configuration of Solid-State Imaging Device>-   (Configuration Example of Solid-State Imaging Device)

FIG. 1 is a diagram depicting a configuration example of an embodimentof the solid-state imaging device to which the present technology isapplied.

A CMOS image sensor 10 in FIG. 1 is an example of a solid-state imagingdevice using a CMOS (Complementary Metal Oxide Semiconductor). The CMOSimage sensor 10 takes in an incident light (image light) from a subjectthrough an optical lens system (not illustrated in the figure), andconverts an amount of incident light from which an image is formed on animaging face into an electric signal in a pixel unit to output theelectric signal as a pixel signal.

In FIG. 1, the CMOS image sensor 10 includes a pixel array section 11, avertical drive circuit 12, column signal processing circuits 13, ahorizontal drive circuit 14, an output circuit 15, a control circuit 16,and an input/output terminal 17.

A plurality of pixels 100 is two-dimensionally arranged (in a matrixform) in the pixel array section 11. The pixels 100 each include aphotodiode (PD) as a photoelectric conversion section and a plurality ofpixel transistors. For example, the pixel transistors include a transfertransistor, a reset transistor, an amplification transistor, and aselection transistor.

The vertical drive circuit 12 includes, for example, a shift register,selects a predetermined pixel drive line 21, and supplies a pulse fordriving the pixels 100 to the selected pixel drive line 21 to drive thepixels 100 in each row. That is, the vertical drive circuit 12selectively scans each pixel 100 in the pixel array section 11 row byrow sequentially in the vertical direction, and supplies the pixelsignals based on signal charges (electric charges) generated in thephotodiode of each pixel 100 according to an amount of the receivedlight to the column signal processing circuits 13 through verticalsignal lines 22.

The column signal processing circuits 13 are arranged for the respectivecolumns of the pixels 100, and process signals output from the pixels100 in one row, for example eliminate noise, for each pixel column. Forexample, the column signal processing circuits 13 perform signalprocessing such as correlated double sampling (CDS) and AD (AnalogDigital) conversion, for removing a fixed pattern noise peculiar to apixel.

The horizontal drive circuit 14 includes, for example, a shift register,sequentially selects each of the column signal processing circuits 13 bysequentially outputting horizontal scanning pulses, and causes each ofthe column signal processing circuits 13 to output a pixel signal to ahorizontal signal line 23.

The output circuit 15 processes and outputs signals sequentiallysupplied from each of the column signal processing circuits 13 throughthe horizontal signal line 23. It is to be noted that, in the outputcircuit 15, for example, only buffering is carried out in some cases,and adjustment of black level, correction of unevenness among columns,various kinds of digital signal processing, and the like are carried outin other cases.

The control circuit 16 controls the operation of each section in theCMOS image sensor 10.

In addition, the control circuit 16 generates clock signals or controlsignals fundamental to operations of the vertical drive circuit 12, thecolumn signal processing circuits 13, the horizontal drive circuit 14,and the like, on the basis of vertical synchronous signals, horizontalsynchronous signals, and master clock signals. The control circuit 16outputs the generated clock signals and control signals to the verticaldrive circuit 12, the column signal processing circuits 13, thehorizontal drive circuit 14, and the like.

The input/output terminal 17 exchanges signals with the outside.

The CMOS image sensor 10 in FIG. 1 configured as described hereinbeforeis regarded as a CMOS image sensor called a column AD type, in which thecolumn signal processing circuits 13 for performing CDS processing andAD conversion processing are arranged for each pixel column. Inaddition, the CMOS image sensor 10 in FIG. 1 can be, for example, aback-illuminated type CMOS image sensor.

<2. Overview of the Present Technology>

-   (Structure of General Pixel)

First, a structure of a general pixel 900 will be explained withreference to the sectional views of FIG. 2 to FIG. 4.

In FIG. 2, in the general pixel 900, an interlayer insulating layer 912and a photoelectric conversion layer 915 are laminated on an upper layerof a semiconductor layer 911. An upper electrode 916 and a lowerelectrode 913 for reading out the charges (signal charges)photoelectrically converted by the photoelectric conversion layer 915are formed on the upper and lower faces of the photoelectric conversionlayer 915.

The charges read out by the upper electrode 916 and the lower electrode913 are accumulated in a floating diffusion (FD) region 921 formed onthe semiconductor layer 911, and converted into voltage signals.

In FIG. 2, between the lower electrodes 913 formed in the pixels 900i.e., between the adjacent lower electrodes 913, a shield electrode 914electrically insulated from the lower electrodes 913 is formed. Theshield electrode 914 is formed so as to surround the lower electrode 913formed on each pixel 900, and the potential (voltage) is fixed.

Incidentally, an extremely large voltage difference between the shieldelectrode 914 and the lower electrode 913 causes a problem that thecharges are injected from the shield electrode 914. FIG. 2 schematicallydepicts a state in which a charge represented by “e-” in the figure isinjected from the shield electrode 914 side to a readout region on thelower electrode 913 side.

In addition, when the voltage difference between the shield electrode914 and the lower electrode 913 is needlessly increased, the chargesdischarged from the shield electrode 914 become high, and the sensorsensitivity is decreased. FIG. 3 schematically depicts a state in whichthe charges represented by “e-” in the figure are needlessly dischargedfrom the shield electrode 914. At this time, a readout region A (regionsurrounded by a dotted line in the figure) on the lower electrode 913side is narrowed, and thus the read-out charges decrease.

On the other hand, an extremely small voltage difference between theshield electrode 914 and the lower electrode 913 causes a problem thatexcess charges too much to read out are generated, resulting in residualimages. FIG. 4 schematically depicts a state in which although an amountof the charges discharged from the shield electrode 914 as the electriccharges represented by “e-” in the figure is small, charges too much toread out are generated because a readout region A (region surrounded bya dotted line in the figure) on the lower electrode 913 side is toowide. At this time, the undischarged charges cannot be read out andremain, resulting in residual images.

As described hereinbefore, since the voltage of the shield electrode 914is not set to an optimum voltage (variable voltage) in the general pixel900, there may be a case in which a too large voltage difference betweenthe shield electrode 914 and the lower electrode 913 is caused (thevoltage of the shield electrode 914 is too high), or a case in which atoo small voltage difference therebetween is caused (the voltage of theshield electrode 914 is too low) are caused.

Thus, in the present technology, the voltage of the shield electrode 914is enabled to be set to an optimum voltage (variable voltage) to adjustthe voltage difference between the shield electrode 914 and the lowerelectrode 913, so that decrease in the sensor sensitivity and generationof residual images can be suppressed, and therefore the properties ofthe pixels can be improved.

-   (Structure of Pixel in the Present Technology)

FIG. 5 is a sectional view depicting the structure of the pixelaccording to the present technology.

FIG. 5 depicts the pixel 100 located at any position among a pluralityof pixels two-dimensionally arranged in the pixel array section 11 ofthe CMOS image sensor 10 in FIG. 1, as an example.

In the pixel 100, an interlayer insulating layer 112 and a photoelectricconversion layer 115 are laminated on an upper layer of a semiconductorlayer 111 such as a silicon substrate. An upper electrode 116 and alower electrode 113 are formed on the upper and lower faces of thephotoelectric conversion layer 115 to read out charges (signal charges)photoelectrically converted by the photoelectric conversion layer 115.

In other words, the upper electrode 116 as the electrode on the lightincidence side and the lower electrode 113 as the electrode on thesilicon substrate side are formed respectively on the light incidenceside and on the silicon substrate side of the photoelectric conversionlayer 115, forming a structure in which the two electrodes sandwich thephotoelectric conversion layer 115 to apply a voltage to thephotoelectric conversion layer 115.

However, the upper electrode 116 is a transparent electrode, formed overthe entire face of the photoelectric conversion layer 115, and common toall the pixels arranged in the pixel array section 11. On the otherhand, the lower electrode 113 is a transparent electrode, and one lowerelectrode 113 is formed for each pixel in accordance with the pixelpitch.

The charges (signal charges) photoelectrically converted by thephotoelectric conversion layer 115 are read out by the upper electrode116 and the lower electrode 113, accumulated in a floating diffusion(FD) region 121 formed in the semiconductor layer 111, and convertedinto voltage signals.

In FIG. 5, between the lower electrodes 113 formed in the pixels 100i.e., between the adjacent lower electrodes 113, a shield electrode 114electrically insulated from the lower electrodes 113 is formed.

FIG. 6 is a plan view in a case in which the shield electrode 114 formedfor the lower electrode 113 is viewed from the light incidence side. Asillustrated in FIG. 6, the shield electrode 114 is formed so as tosurround the lower electrode 113 formed in each pixel 100.

In the present technology, in the pixel 100, the voltage of the shieldelectrode 114 formed between the adjacent lower electrodes 113 iscontrolled to an optimum voltage (variable voltage) to adjust thevoltage difference between the shield electrode 114 and the lowerelectrode 113, so that the property of the pixel 100 is improved.

Hereinafter, specific contents of the present technology will beexplained with reference to the first to fourth embodiments.

3. First Embodiment

(First Pixel Structure)

First, the structure of the pixel 100 according to the first embodimentwill be explained with reference to the sectional views of FIG. 7 toFIG. 9.

In the pixel 100, the voltage of the shield electrode 114 formed betweenthe adjacent lower electrodes 113 can be set to a voltage allowingexcess charges too much to read out to be discharged from the shieldelectrode 114, or a voltage allowing the readout region on the lowerelectrode 113 side to be within such a range that prevents decrease insensitivity.

FIG. 7 schematically depicts a state in which excess charges too much toread out as the charges represented by “e-” in the figure are dischargedfrom the shield electrode 114. In FIG. 7, a readout region A on thelower electrode 113 side (region surrounded by a dotted line in thefigure) is within such a range that prevents decrease in the sensorsensitivity, and therefore, as the charges represented by the “e-” inthe figure, the charges which can be read out do not decrease.

In the pixel 100, the voltage of the shield electrode 114 can be limitedto a range where an electric current does not flow between the shieldelectrode 114 and the lower electrode 113. FIG. 8 schematically depictsa state in which the electric current (leak current) is prevented fromflowing in directions of arrows in the figure between the shieldelectrode 114 and the lower electrode 113 by limiting the voltage of theshield electrode 114.

Then, in the pixel 100 according to the first embodiment, the voltageallowing excess charges too much to read out to be discharged from theshield electrode 114, or the voltage allowing the readout region A onthe lower electrode 113 side to be within such a range that preventsdecrease in sensitivity is set as an optimum voltage for the shieldelectrode 114.

It is to be noted here that the optimum voltage refers to a voltage ofthe shield electrode 114 which maximizes the sensor sensitivity withoutcausing the leak current from the shield electrode 114 to the lowerelectrode 113, and without causing the excess charges too much to readout.

FIG. 9 schematically depicts a state in which the voltage of the shieldelectrode 114 expressed by a region B in the figure is controlled to bean optimum voltage to discharge the excess charges too much to read outas the charges represented by “e-” in the figure, from the shieldelectrode 114. In this case, unnecessary charges can be discharged tosuppress generation of excess charges too much to read out, and therebyresidual images can be suppressed.

In FIG. 9, the readout region A on the lower electrode 113 side iswithin such a range that prevents decrease in the sensor sensitivity bycontrolling the voltage of the shield electrode 114 to an optimumvoltage. Thus, the read-out charges as the charges represented by “e-”in the figure do not decrease. In this case, readout of the charges isassisted, more charges are taken in, and thus decrease in the sensorsensitivity can be suppressed.

As described hereinbefore, in the pixel 100 according to the firstembodiment, an optimum voltage for the shield electrode 114 formedbetween the adjacent lower electrodes 113 is detected, and the optimumvoltage is set as the voltage of the shield electrode 114. Hereinafter,as such an optimum voltage control method, first to fifth controlmethods will be explained.

(1) First Control Method

First, the first control method will be explained with reference toFIGS. 10A, 10B, 11A, 11B, and 12. In this first control method, thevoltage of the shield electrode 114 during exposure is set to an optimumvoltage according to output of a frame obtained before the exposure(hereinafter, referred to as a previous frame image).

FIGS. 10A and 10B depict an example of control in a case in which abright image is obtained as the previous frame image. FIGS. 10A and 10Bdepict a state in which, in a case in which a bright image asillustrated in FIG. 10A is obtained as a previous frame image F1,control as illustrated in FIG. 10B is performed during exposure.

That is, in a case in which a level (for example, level of contrast,luminance, or the like) corresponding to the previous frame image F1 ishigher than a predetermined threshold value and the previous frame imageF1 is determined as a bright image, the voltage set for the shieldelectrode 114 during exposure is lowered to discharge unnecessarycharges.

FIG. 10B schematically depicts a state in which unnecessary charges aredischarged from the shield electrode 114 for which a low voltage is set.As described hereinbefore, unnecessary charges are discharged tosuppress generation of excess charges too much to read out, so thatgeneration of residual images on a captured image (frame image obtainedafter the previous frame image) can be suppressed

On the other hand, FIGS. 11A and 11B depict an example of control in acase in which a dark image is obtained as the previous frame image.FIGS. 11A and 11B depict a state in which, in a case in which a darkimage as illustrated in FIG. 11A is obtained as a previous frame imageF2, control as illustrated in FIG. 11B is performed during exposure.

That is, in a case in which a level (for example, level of contrast,luminance, or the like) corresponding to the previous frame image F2 islower than a predetermined threshold value and the previous frame imageF2 is determined as a dark image, the voltage set for the shieldelectrode 114 during exposure is increased to take in more charges.

FIG. 11B schematically depicts a state in which, in a case in which ahigh voltage is set for the shield electrode 114, more charges are takenin in the readout region A on the lower electrode 113 side. As describedhereinbefore, the shield electrode 114 assists the charge transfer totake in more charges, so that decrease in the sensor sensitivity can besuppressed.

FIG. 12 depicts a configuration in a case in which the voltage of theshield electrode 114 corresponding to output of the previous frame imageis set by an external control circuit 50.

In FIG. 12, the control circuit 50 performs control (feedback control)such that the voltage set for the shield electrode 114 during exposureis optimum, on the basis of the result of analyzing the previous imageframe output from the CMOS image sensor 10.

Specifically, in a case in which the previous frame image is determinedas a bright image, the control circuit 50 sets the voltage of the shieldelectrode 114 to a low value, and in a case in which the previous frameimage is determined as a dark image, the control circuit 50 sets thevoltage of the shield electrode 114 to a high value.

In this feedback control, the level of the voltage set for the shieldelectrode 114 by the control circuit 50 is determined depending on thevoltage difference from the voltage of the lower electrode 113. In acase in which the voltage of the lower electrode 113 is low, the chargetransfer can be assisted by increasing the voltage of the shieldelectrode 114. On the other hand, in a case in which the voltage of thelower electrode 113 is high, unnecessary charges can be discharged bydecreasing the voltage of the shield electrode 114. In addition, thelevel of the voltage set for the shield electrode 114 can be determineddepending on, for example, an amount of charges to be assisted for thetransfer, an amount of unnecessary charges to be discharged, or thelike.

As the threshold value used in the determination described hereinbefore,an arbitrary value can be set according, for example, to a determinationcriterion of whether the previous frame image is a bright image or adark image, and the like.

Although FIG. 12 depicts the configuration in which the control circuit50 is disposed outside the CMOS image sensor 10, the control circuit 50may be disposed inside the CMOS image sensor 10. In this case, feedbackcontrol in accordance with the first control method is performed by thecontrol circuit 50 inside the CMOS image sensor 10.

(2) Second Control Method

Next, the second control method will be explained with reference toFIGS. 13A, 13B, 13C, and 13D. In this second control method, accordingto a reset level output of the pixel 100, the voltage of the shieldelectrode 114 during a signal level output is set to an optimum voltage.

Correlated double sampling (CDS) is intended to obtain signal componentsfrom which noise components are removed, by taking a difference betweenthe reset level obtained after reset and the signal level obtainedduring exposure. In the second control method, the voltage of the shieldelectrode 114 can be set to an optimum voltage by utilizing theprinciple of this correlated double sampling (CDS).

FIGS. 13A, 13B, 13C, and 13D depicts a series of control flow inaccordance with the second control method utilizing the principle ofcorrelated double sampling (CDS).

In FIGS. 13A, 13B, 13C, and 13D, a sensor section 30 corresponds to thewhole or a part of the pixel array section 11 of the CMOS image sensor10 (FIG. 1), and includes the two-dimensionally arranged pixels 100.Additionally, in FIGS. 13A, 13B, 13C, and 13D, a CDS circuit 40corresponds to the whole or a part of the column signal processingcircuit 13 in the CMOS image sensor 10 (FIG. 1), and performs thecorrelated double sampling (CDS).

First, as illustrated in FIG. 13A, in the sensor section 30, thefloating diffusion region 121 in the pixel 100 is reset during a resetperiod temporally before an exposure period, and the resulting resetlevel is output to the CDS circuit 40.

Next, as illustrated in FIG. 13B, in the CDS circuit 40, the voltage ofthe shield electrode 114 during the signal level output (exposure) iscontrolled (feedback-controlled) according to the reset level outputfrom the sensor section 30.

That is, in a case in which the level corresponding to the reset levelis higher than a predetermined threshold value, the voltage set for theshield electrode 114 during the signal level output is decreased todischarge unnecessary charges. On the other hand, in a case in which thelevel corresponding to the reset level is lower than the predeterminedthreshold value, the voltage set for shield electrode 114 during thesignal level output is increased to assist the charge transfer.

Next, as illustrated in FIG. 13C, in the sensor section 30, charges areaccumulated in the floating diffusion region 121 in the pixel 100 duringexposure, and a signal level corresponding to the charges is read outand output to the CDS circuit 40.

At this time, in the pixel 100, the voltage of the shield electrode 114is feedback-controlled from the CDS circuit 40, and thus in a case inwhich the reset level is high, the voltage of the shield electrode 114is set to a low value to discharge unnecessary charges. Hence,generation of residual images on the captured image can be suppressed.In addition, in a case in which the reset level is low, the voltage ofthe shield electrode 114 is set to a high value to take in more charges.Hence, decrease in the sensor sensitivity can be suppressed.

Finally, as illustrated in FIG. 13D, in the CDS circuit 40, correlateddouble sampling (CDS) is performed by taking the difference between thereset level output from the sensor section 30 and the signal level, anda post-CDS captured image obtained from the signal components from whichthe noise components have been removed is output.

Incidentally, as a threshold value used in the determination describedhereinbefore, any value can be set according, for example, to adetermination criterion for the level of the reset level output, or thelike.

Although FIGS. 13A, 13B, 13C, and 13D depict the configuration in which,as the column signal processing circuit 13 (FIG. 1), the CDS circuit 40is disposed inside the CMOS image sensor 10, the CDS circuit 40 may bedisposed outside the CMOS image sensor 10. In this case, feedbackcontrol in accordance with the second control method is performed by theCDS circuit 40 disposed outside the CMOS image sensor 10.

(3) Third Control Method

Next, the third control method will be explained with reference to FIG.14. In the third control method, the voltage of the shield electrode 114during imaging is set to an optimum voltage according to the result ofdetecting the temperature obtained from a temperature sensor.

FIG. 14 depicts a configuration in a case in which the external controlcircuit 50 sets the voltage of the shield electrode 114 according to theresult of detecting the temperature from a temperature sensor 35.

In FIG. 14, the temperature sensor 35 is disposed inside the CMOS imagesensor 10 together with the sensor section 30. The sensor section 30corresponds to the whole or a part of the pixel array section 11 (FIG.1), and includes the two-dimensionally arranged pixels 100. That is, inFIG. 14, the temperature sensor 35 is disposed in the vicinity of thepixel 100 disposed on the sensor section 30.

Although the configuration of FIG. 14 depicts a case in which thetemperature sensor 35 is disposed inside the CMOS image sensor 10 as anexample, the temperature sensor 35 may be disposed outside the CMOSimage sensor 10.

The temperature sensor 35 regularly detects the temperature inside theCMOS image sensor 10 and outputs the result of detecting the temperatureto the control circuit 50.

The control circuit 50 controls (feedback-controls) the voltage of theshield electrode 114 during imaging, according to the result ofdetecting the temperature output from the temperature sensor 35.

That is, in a case in which the level corresponding to the temperaturedetected by the temperature sensor 35 is higher than a predeterminedthreshold value, the voltage set for the shield electrode 114 duringimaging is decreased to discharge unnecessary charges. As a result,generation of residual images on the captured image can be suppressed.

On the other hand, in a case in which the level corresponding to thetemperature detected by the temperature sensor 35 is lower than thepredetermined threshold value, the voltage set for the shield electrode114 during imaging is increased to assist the charge transfer. As aresult, decrease in the sensor sensitivity can be suppressed.

Incidentally, as a threshold value used in the determination describedhereinbefore, any value can be set according, for example, to thedetermination criterion for the level of the detected temperature, orthe like.

Although FIG. 14 depicts the configuration in which the control circuit50 is disposed outside the CMOS image sensor 10, the control circuit 50may be disposed inside the CMOS image sensor 10. In this case, thecontrol circuit 50 inside the CMOS image sensor 10 performs the feedbackcontrol in accordance with the third control method.

(4) Fourth Control Method

Next, the fourth control method will be explained with reference to FIG.15. In the fourth control method, the voltage of the shield electrode114 during imaging is set to an optimum voltage according to output of alight-shielding pixel.

FIG. 15 depicts a configuration in a case in which the external controlcircuit 50 sets the voltage of the shield electrode 114 disposed for avalid pixel 31 according to output of a light-shielding pixel 32.

In FIG. 15, the sensor section 30 corresponds to the whole or a part ofthe pixel array section 11 (FIG. 1) and includes two-dimensionallyarranged pixels 100. That is, among the plurality of pixels 100two-dimensionally arrayed on the sensor section 30, the valid pixels 31and the light-shielding pixels 32 are arbitrary pixels, and pixels otherthan the light-shielding pixels 32 are regarded as the valid pixels 31.

Here, the light-shielding pixel 32 is also referred to as an OPB(Optical Black) pixel and has a structure similar to that of the validpixel 31, but is configured such that light is shielded by a lightshielding film and thus an incident light does not reach. A blackreference can be determined by signals output from this light-shieldingpixel 32. For example, the light-shielding pixels 32 are arranged around(in a nearby area of) an area on which the valid pixel 31 is arranged.

The control circuit 50 controls (feedback-controls) the voltage of theshield electrode 114 of the valid pixel 31 during imaging, according tothe signals output from the light-shielding pixel 32.

That is, in a case in which the level corresponding to the output fromthe light-shielding pixel 32 is higher than a predetermined thresholdvalue, the voltage set for the shield electrode 114 disposed for thevalid pixel 31 during imaging is decreased to discharge unnecessarycharges. As a result, generation of residual images on the capturedimage can be suppressed.

On the other hand, in a case in which the level corresponding to theoutput from the light-shielding pixel 32 is lower than the predeterminedthreshold value, the voltage set for the shield electrode 114 disposedfor the valid pixel 31 during imaging is increased to assist the chargetransfer. As a result, decrease in the sensor sensitivity can besuppressed.

Incidentally, as a threshold value used in the determination describedhereinbefore, any value can be set according, for example, to adetermination criterion for the output level of the light-shieldingpixel 32, or the like.

Although FIG. 15 depicts the configuration in which the control circuit50 is disposed outside the CMOS image sensor 10, the control circuit 50may be disposed inside the CMOS image sensor 10. In this case, thecontrol circuit 50 inside the CMOS image sensor 10 performs the feedbackcontrol in accordance with the fourth control method.

(5) Fifth Control Method

Finally, the fifth control method will be explained with reference toFIG. 16. In the fifth control method, the voltage of the shieldelectrode 114 during imaging is set to an optimum voltage according to again set for the CMOS image sensor 10.

FIG. 16 depicts a configuration in a case in which the external controlcircuit 50 sets the voltage of the shield electrode 114 according to theset gain.

The control circuit 50 sets a gain for the CMOS image sensor 10. Inaddition, the control circuit 50 controls (feedback-controls) thevoltage of the shield electrode 114 during imaging, according to apreset gain.

That is, in a case in which the level corresponding to the preset gainis lower than a predetermined threshold value, the voltage set for theshield electrode 114 is decreased to discharge unnecessary charges. As aresult, generation of residual images on the captured image can besuppressed.

On the other hand, in a case in which the level corresponding to thepreset gain is higher than the predetermined threshold value, thevoltage set to the shield electrode 114 is increased to assist thecharge transfer. As a result, decrease in the sensor sensitivity can besuppressed.

Incidentally, as a threshold value used in the determination describedhereinbefore, any value can be set according, for example, to adetermination criterion for the level of the set gain, or the like.

Although FIG. 16 depicts the configuration in which the control circuit50 is disposed outside the CMOS image sensor 10, the control circuit 50may be disposed inside the CMOS image sensor 10. In this case, thecontrol circuit 50 inside the CMOS image sensor 10 performs the feedbackcontrol in accordance with the fifth control method.

Although the first to fifth control methods are explained hereinbeforeas the control method according to the first embodiment, these controlmethods are merely examples, and other control methods may be used.

4. Second Embodiment

(Second Pixel Structure)

Next, a pixel structure according of the second embodiment will beexplained with reference to FIG. 17 and FIG. 18.

FIG. 17 is a sectional view depicting the pixel structure according tothe second embodiment.

In the pixel 100 of FIG. 17, the lower electrode 113 describedhereinbefore (FIG. 5 and the like) is divided into an accumulationelectrode 131, a transfer electrode 132, and a readout electrode 133. Inaddition, an insulation film 141 is formed on the lower face of thephotoelectric conversion layer 115 except for a part of the upper faceof the readout electrode 133.

The accumulation electrode 131 is an electrode for accumulating charges.The transfer electrode 132 is an electrode for transferring the chargesaccumulated in the accumulation electrode 131. The readout electrode 133is an electrode for reading out the charges transferred from thetransfer electrode 132.

The charges photoelectrically converted by the photoelectric conversionlayer 115 are read out by the upper electrode 116 and the readoutelectrode 133, accumulated in a floating diffusion region (FD) formed inthe semiconductor layer 111, and converted into voltage signals.

FIG. 18 is a plan view in a case in which the shield electrode 114formed for the accumulation electrode 131, the transfer electrode 132,and the readout electrode 133 is viewed from the light incidence side.As illustrated in FIG. 18, the shield electrode 114 is formed so as tosurround the accumulation electrode 131, the transfer electrode 132, andthe readout electrode 133 which are formed on each pixel 100.

In the second embodiment, the voltage of the shield electrode 114 formedbetween the accumulation electrodes 131, the transfer electrodes 132,and the readout electrodes 133 in the adjacent pixels 100 can becontrolled to an optimum voltage to improve the property of the pixel100.

In the second embodiment, as the method for controlling the voltage ofthe shield electrode 114 to an optimum voltage, any control method amongthe first to the fifth control methods explained hereinbefore in thefirst embodiment can be used.

5. Third Embodiment

(Third Pixel Structure)

Next, a pixel structure according to the third embodiment will beexplained with reference to FIG. 19 and FIG. 21.

Since a sectional structure of the pixel 100 according to the thirdembodiment is similar to the sectional structure of the pixel 100illustrated in FIG. 5, explanation thereof is omitted in the thirdembodiment.

FIG. 19 to FIG. 21 are plan views in a case in which the shieldelectrode 114 formed for the lower electrode 113 is viewed from thelight incidence side. As illustrated in FIG. 19 to FIG. 21, the shieldelectrode 114 is formed so as to surround the lower electrode 113 whichis formed for each pixel 100.

FIG. 19 depicts a configuration in a case in which one shield electrode114 is disposed for all the pixels.

In FIG. 19, one shield electrode 114 is lattice-likely formed for allthe pixels 100 two-dimensionally arranged in the pixel array section 11(FIG. 1), and the lower electrodes 113 formed for the respective pixels100 are surrounded by the common shield electrode 114.

In this case, the voltage of the shield electrode 114 is controlled inall the pixels in common. For this reason, the voltage of the shieldelectrode 114 can be more easily controlled to an optimum voltagecompared to a case in which control is performed by a one-pixel unit ora plural-pixel unit.

FIG. 20 depicts a configuration in a case in which one shield electrode114 is disposed for one pixel.

In FIG. 20, one shield electrode 114 is formed in a square shape on eachof pixels 100 two-dimensionally arranged in the pixel array section 11(FIG. 1), and the lower electrodes 113 formed for the respective pixels100 are individually surrounded by the different shield electrodes 114.

In this case, the voltage of the shield electrode 114 can be controlledfor each pixel. Thus, the voltage of the shield electrode 114 can bemore finely controlled to an optimum voltage, compared to a case inwhich the control is performed by an all-pixel unit or a plural-pixelunit. However, in FIG. 20, the voltage may be controlled not only foreach pixel, but also in all the pixels in common, or by the plural-pixelunit.

FIG. 21 depicts a configuration in a case in which one shield electrode114 is disposed for a plurality of pixels.

In FIG. 21, one shield electrode 114 is formed for each unit of groupedplural pixels two-dimensionally arranged in the pixel array section 11(FIG. 1), and the lower electrodes 113 formed on the respective pixels100 are surrounded by the common shield electrode 114 in each group. Forexample, in the example of FIG. 21, pixels are grouped by a four-pixelunit, and one shield electrode 114 is four-squarely formed for fourpixels.

In this case, the voltage of the shield electrode 114 can be controlledby the plural-pixel unit. For this reason, the voltage of the shieldelectrode 114 can be more finely controlled to an optimum voltagecompared to a case in which the control is performed for all the pixelsin common. In addition, the voltage of the shield electrode 114 can bemore easily controlled to an optimum voltage compared to a case in whichthe control is performed by a one-pixel unit. However, in FIG. 21, thevoltage may be controlled not only by the plural-pixel unit but also forall the pixels in common.

In the third embodiment, the voltage of the shield electrode 114 formedbetween the lower electrodes 113 of the adjacent pixels 100 can becontrolled to an optimum voltage to improve the property of the pixel100.

In the third embodiment, as the method for controlling the voltage ofthe shield electrode 114 to an optimum voltage, any control method amongthe first to the fifth control methods explained hereinbefore in thefirst embodiment can be used.

In the above explanation, although the lower electrode 113 formed foreach pixel 100 is explained as being surrounded by the shield electrode114, it is sufficient that the shield electrode 114 is formed on atleast one side of four sides of the lower electrode 113.

For example, in a case in which one shield electrode 114 isfour-squarely formed for four pixels as illustrated in FIG. 21, thecross-shaped portion of the shield electrode 114 may be omitted.However, the property of the pixel 100 can be more improved in the casein which the circumference of the lower electrode 113 is surrounded bythe shield electrode 114.

6. Fourth Embodiment

(Fourth Pixel Structure)

Next, a pixel structure according to the fourth embodiment will beexplained with reference to FIG. 22.

Since a sectional structure of the pixel 100 according to the fourthembodiment is basically similar to the sectional structure of the pixel100 illustrated in FIG. 5, explanation thereof is omitted here.

FIG. 22 is a plan view in a case in which the shield electrode 114formed for the lower electrode 113 is viewed from the light incidenceside. As illustrated in FIG. 22, a shield electrode 114-1 and a shieldelectrode 114-2 are formed so as to doubly surround the lower electrode113 formed for each pixel 100.

In FIG. 22, the two shield electrodes 114-1 and 114-2 are formed intosquare shapes having different sizes for each of the pixels 100two-dimensionally arranged in the pixel array section 11 (FIG. 1), andthe lower electrodes 113 formed for the respective pixels 100 are doublysurrounded by different shield electrodes 114-1 and 114-2.

In this case, the voltages of the two shield electrodes 114-1 and 114-2can be controlled for each pixel. At this time, the shield electrodes114-1 and 114-2 may be controlled in common or individually controlled.Thus, the voltage of the shield electrode 114 can be more finelycontrolled to an optimum voltage compared to a case in which the controlis performed for all the pixels in common or by the plural-pixel unit.However, the voltage may be controlled not only by the one-pixel unit,but also for all the pixels in common or by the plural-pixel unit.

In the fourth embodiment, the voltages of the shield electrodes 114-1and 114-2 formed between the lower electrodes 113 of the adjacent pixels100 can be controlled to optimum voltages to improve the property of thepixel 100.

In the fourth embodiment, as the method for controlling the voltage ofthe shield electrode 114 to an optimum voltage, any control method amongthe first to the fifth control methods explained hereinbefore in thefirst embodiment can be used.

In the above explanation, although the case in which the lower electrode113 formed for each pixel 100 is doubly surrounded by the shieldelectrode 114-1 and the shield electrode 114-2 is described, the lowerelectrode 113 may be surrounded triply or more by increased number ofshield electrodes 114. For example, in this case, the voltage can bemore finely controlled by individually controlling each of the shieldelectrodes 114 formed in superposition.

(Summary)

As described hereinbefore, in the present technology, on the premise tocontrol the voltage of the shield electrode 114 described in the firstembodiment to an optimum voltage, the structures described in the secondto fourth embodiments can be adopted.

FIG. 23 represents an example of the voltage of the shield electrode114, which is set in a case in which the gain, the temperature, and thelight amount are taken as factors in the control method described in thefirst embodiment.

In a case in which the gain is high, the voltage of the lower electrode113 is low, and therefore the voltage of the shield electrode 114 is setto a high value for the purpose of assisting the charge transfer. On theother hand, in a case in which the gain is low, the voltage of the lowerelectrode 113 is high, and therefore the voltage of the shield electrode114 is set to a low value for the purpose of discharging the charges.

In a case in which the temperature is high, the charges are easy to readout, and therefore the voltage of the shield electrode 114 is set to alow value for the purpose of discharging the charges. On the other hand,in a case in which the temperature is low, the charges are difficult toread out, and therefore the voltage of the shield electrode 114 is setto a high value for the purpose of assisting the charge transfer.

In a case in which the light amount is large, the voltage of the lowerelectrode 113 is high, and therefore the voltage of the shield electrode114 is set to a low value for the purpose of discharging the charges. Onthe other hand, in a case in which the light amount is small, thevoltage of the lower electrode 113 is low, and therefore the voltage ofthe shield electrode 114 is set to a high value for the purpose ofassisting the charge transfer.

As described hereinbefore, the control method described in the firstembodiment performs control such that the voltage of the shieldelectrode 114 is set to an optimum voltage according to the detectionresult which may contribute to control of the discharge or transfer ofcharges. This detection result can include at least one of the detectionresults regarding the light amount (including the gain) or thetemperature.

7. Modification Example

In the above explanation, although the CMOS image sensor (FIG. 1) isexplained as a back-illuminated type, another structure of, for example,a front-illuminated type or the like may be adopted. In the aboveexplanation, although the CMOS image sensor 10 is explained as thesolid-state imaging device, the present technology can also be appliedto other image sensors, for example, a CCD (Charge Coupled Device) imagesensor or the like.

In the above explanation, the control circuit 50 is explained as beingdisposed outside or inside the CMOS image sensor 10, but in a case inwhich the control circuit 50 is disposed outside the CMOS image sensor10, the control circuit 50 is configured as, for example, a CPU (CentralProcessing Unit) to allow the control with software processing. In acase in which the control circuit 50 is disposed inside the CMOS imagesensor 10, the control circuit 50 may be in common with or differentfrom the control circuit 16 (FIG. 1).

<8. Configuration of Electronic Apparatus>

FIG. 24 is a block diagram depicting a configuration example of anelectronic apparatus having a solid-state imaging device to which thepresent technology is applied.

An electronic apparatus 1000 is, for example, an electronic apparatusincluding an imaging device such as a digital still camera and a videocamera, a portable terminal device such as a smartphone and a tablettype terminal, or the like.

The electronic apparatus 1000 includes a solid-state imaging device1001, a DSP circuit 1002, a frame memory 1003, a display section 1004, arecording section 1005, an operation section 1006, and a power section1007. In the electronic apparatus 1000, the DSP circuit 1002, the framememory 1003, the display section 1004, the recording section 1005, theoperation section 1006, and the power section 1007 are connected witheach other via a bus line 1008.

The solid-state imaging device 1001 corresponds to the CMOS image sensor10 (FIG. 1) described hereinbefore. For the pixels 100 two-dimensionallyarranged in the pixel array section (FIG. 1), control is performed suchthat an optimal voltage is set as the voltage of the shield electrode114 formed between the adjacent lower electrodes 113.

The DSP circuit 1002 is a camera signal processing circuit forprocessing signals supplied from the solid-state imaging device 1001.The DSP circuit 1002 outputs image data obtained by processing signalsfrom the solid-state imaging device 1001. The frame memory 1003temporarily holds the image data processed by the DSP circuit 1002 by aframe unit.

The display section 1004 includes, for example, a panel type displaydevice such as a liquid crystal panel and an organic EL (ElectroLuminescence) panel, and displays a moving image or a still imagecaptured by the solid-state imaging device 1001. The recording section1005 records image data of the moving image or the still image capturedby the solid-state imaging device 1001 in a recording medium such as asemiconductor memory and a hard disk.

The operation section 1006 outputs operation commands for variousfunctions of the electronic apparatus 1000 in accordance with theoperation by the user. The power section 1007 suitably supplies variouspowers as operation powers to the DSP circuit 1002, the frame memory1003, the display section 1004, the recording section 1005 and theoperation section 1006 to these supply targets.

The electronic apparatus 1000 is configured as described hereinbefore.The present technology is applied to the solid-state imaging device 1001as explained hereinbefore. Specifically, the CMOS image sensor 10(FIG. 1) can be applied to the solid-state imaging device 1001. With thepresent technology applied to the solid-state imaging device 1001, ineach pixel 100, an optimum voltage is set as the voltage of the shieldelectrode 114 formed between the adjacent lower electrodes 113. Thus,the pixel property can be improved to suppress generation of residualimages and decrease in the sensor sensitivity.

<9. Usage Example of Solid-State Imaging Device>

FIG. 25 is a diagram depicting a usage example of the solid-stateimaging device to which the present technology is applied.

The CMOS image sensor 10 (FIG. 1) can be used, for example, in variouscases for sensing light such as visible light, infrared light,ultraviolet light and X-ray as described hereinafter. That is, asillustrated in FIG. 25, the CMOS image sensor 10 can be used not onlyfor devices used in the field of appreciation in which images forappreciation are captured, but also for devices used in the field oftraffic, the field of home electric appliances, the field of medical andhealth care, the field of security, the field of beauty, the field ofsports, the field of agriculture, or the like.

Specifically, in the field of appreciation, the CMOS image sensor 10 canbe used, for example, in a device (electronic apparatus 1000 in FIG. 24,for example) for capturing an image for appreciation, such as a digitalcamera, a smartphone, and a mobile phone with a camera function.

In the field of traffic, the CMOS image sensor 10 can be used in adevice used for traffic such as an in-vehicle sensor for imaging front,rear, circumference, inside, and the like of an automobile, a monitorcamera for monitoring traveling vehicles and roads, a ranging sensor formeasuring a distance between vehicles or the like, for example, for thepurpose of safe driving such as automatic stop, recognition of driver'scondition, and the like.

In the field of home electric appliances, the CMOS image sensor 10 canbe used in a device for home electric appliances such as a televisionreceiver, a refrigerator and an air conditioner, for example, for thepurpose of imaging a user's gesture and operating an apparatus inaccordance with the gesture. In the the field of medical and healthcare, the CMOS image sensor 10 can be used, for example, in a device formedical care and health care, such as an endoscope and a device forangiography with a received infrared light.

In the field of security, the CMOS image sensor 10 can be used, forexample, in a device for security, such as a crime preventing monitorcamera and a person authentication camera. In the the field of beauty,the CMOS image sensor 10 can be used, for example, in a device forbeauty, such as a skin measuring instrument for imaging skin and amicroscope for imaging scalp.

In the field of sports, the CMOS image sensor 10 can be used, forexample, in a device for sports, such as an action camera and a wearablecamera for sports or the like. In the the field of agriculture, the CMOSimage sensor 10 can be used, for example, in a device for agriculturesuch as a camera for monitoring conditions of fields and crops.

<10. Application Example to Mobile Bodies>

The technology according to the present disclosure (the presenttechnology) can be applied to various products. For example, thetechnology according to the present disclosure may be implemented as adevice mounted on any type of mobile body, such as an automobile, anelectric automobile, a hybrid electric automobile, a motorcycle, abicycle, a personal mobility, an airplane, a drone, a ship, and a robot.

FIG. 26 is a block diagram depicting an example of schematicconfiguration of a vehicle control system as an example of a mobile bodycontrol system to which the technology according to an embodiment of thepresent disclosure can be applied.

The vehicle control system 12000 includes a plurality of electroniccontrol units connected to each other via a communication network 12001.In the example depicted in FIG. 26, the vehicle control system 12000includes a driving system control unit 12010, a body system control unit12020, an outside-vehicle information detecting unit 12030, anin-vehicle information detecting unit 12040, and an integrated controlunit 12050. In addition, a microcomputer 12051, a sound/image outputsection 12052, and a vehicle-mounted network interface (I/F) 12053 areillustrated as a functional configuration of the integrated control unit12050.

The driving system control unit 12010 controls the operation of devicesrelated to the driving system of the vehicle in accordance with variouskinds of programs. For example, the driving system control unit 12010functions as a control device for a driving force generating device forgenerating the driving force of the vehicle, such as an internalcombustion engine, a driving motor, or the like, a driving forcetransmitting mechanism for transmitting the driving force to wheels, asteering mechanism for adjusting the steering angle of the vehicle, abraking device for generating the braking force of the vehicle, and thelike.

The body system control unit 12020 controls the operation of variouskinds of devices provided to a vehicle body in accordance with variouskinds of programs. For example, the body system control unit 12020functions as a control device for a keyless entry system, a smart keysystem, a power window device, or various kinds of lamps such as aheadlamp, a backup lamp, a brake lamp, a turn signal, a fog lamp, or thelike. In this case, radio waves transmitted from a mobile device as analternative to a key or signals of various kinds of switches can beinput to the body system control unit 12020. The body system controlunit 12020 receives these input radio waves or signals, and controls adoor lock device, the power window device, the lamps, or the like of thevehicle.

The outside-vehicle information detecting unit 12030 detects informationabout the outside of the vehicle including the vehicle control system12000. For example, the outside-vehicle information detecting unit 12030is connected with an imaging section 12031. The outside-vehicleinformation detecting unit 12030 makes the imaging section 12031 imagean image of the outside of the vehicle, and receives the imaged image.On the basis of the received image, the outside-vehicle informationdetecting unit 12030 may perform processing of detecting an object suchas a human, a vehicle, an obstacle, a sign, a character on a roadsurface, or the like, or processing of detecting a distance thereto.

The imaging section 12031 is an optical sensor that receives light, andwhich outputs an electric signal corresponding to a received lightamount of the light. The imaging section 12031 can output the electricsignal as an image, or can output the electric signal as informationabout a measured distance. In addition, the light received by theimaging section 12031 may be visible light, or may be invisible lightsuch as infrared rays or the like.

The in-vehicle information detecting unit 12040 detects informationabout the inside of the vehicle. The in-vehicle information detectingunit 12040 is, for example, connected with a driver state detectingsection 12041 that detects the state of a driver. The driver statedetecting section 12041, for example, includes a camera that images thedriver. On the basis of detection information input from the driverstate detecting section 12041, the in-vehicle information detecting unit12040 may calculate a degree of fatigue of the driver or a degree ofconcentration of the driver, or may determine whether the driver isdozing.

The microcomputer 12051 can calculate a control target value for thedriving force generating device, the steering mechanism, or the brakingdevice on the basis of the information about the inside or outside ofthe vehicle which information is obtained by the outside-vehicleinformation detecting unit 12030 or the in-vehicle information detectingunit 12040, and output a control command to the driving system controlunit 12010. For example, the microcomputer 12051 can perform cooperativecontrol intended to implement functions of an advanced driver assistancesystem (ADAS) which functions include collision avoidance or shockmitigation for the vehicle, following driving based on a followingdistance, vehicle speed maintaining driving, a warning of collision ofthe vehicle, a warning of deviation of the vehicle from a lane, or thelike.

In addition, the microcomputer 12051 can perform cooperative controlintended for automatic driving, which makes the vehicle to travelautonomously without depending on the operation of the driver, or thelike, by controlling the driving force generating device, the steeringmechanism, the braking device, or the like on the basis of theinformation about the outside or inside of the vehicle which informationis obtained by the outside-vehicle information detecting unit 12030 orthe in-vehicle information detecting unit 12040.

In addition, the microcomputer 12051 can output a control command to thebody system control unit 12020 on the basis of the information about theoutside of the vehicle which information is obtained by theoutside-vehicle information detecting unit 12030. For example, themicrocomputer 12051 can perform cooperative control intended to preventa glare by controlling the headlamp so as to change from a high beam toa low beam, for example, in accordance with the position of a precedingvehicle or an oncoming vehicle detected by the outside-vehicleinformation detecting unit 12030.

The sound/image output section 12052 transmits an output signal of atleast one of a sound and an image to an output device capable ofvisually or auditorily notifying information to an occupant of thevehicle or the outside of the vehicle. In the example of FIG. 26, anaudio speaker 12061, a display section 12062, and an instrument panel12063 are illustrated as the output device. The display section 12062may, for example, include at least one of an on-board display and ahead-up display.

FIG. 27 is a diagram depicting an example of the installation positionof the imaging section 12031.

In FIG. 27, the imaging section 12031 includes imaging sections 12101,12102, 12103, 12104, and 12105.

The imaging sections 12101, 12102, 12103, 12104, and 12105 are, forexample, disposed at positions on a front nose, sideview mirrors, a rearbumper, and a back door of the vehicle 12100 as well as a position on anupper portion of a windshield within the interior of the vehicle. Theimaging section 12101 provided to the front nose and the imaging section12105 provided to the upper portion of the windshield within theinterior of the vehicle obtain mainly an image of the front of thevehicle 12100. The imaging sections 12102 and 12103 provided to thesideview mirrors obtain mainly an image of the sides of the vehicle12100. The imaging section 12104 provided to the rear bumper or the backdoor obtains mainly an image of the rear of the vehicle 12100. Theimaging section 12105 provided to the upper portion of the windshieldwithin the interior of the vehicle is used mainly to detect a precedingvehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, orthe like.

Incidentally, FIG. 27 depicts an example of photographing ranges of theimaging sections 12101 to 12104. An imaging range 12111 represents theimaging range of the imaging section 12101 provided to the front nose.Imaging ranges 12112 and 12113 respectively represent the imaging rangesof the imaging sections 12102 and 12103 provided to the sideviewmirrors. An imaging range 12114 represents the imaging range of theimaging section 12104 provided to the rear bumper or the back door. Abird's-eye image of the vehicle 12100 as viewed from above is obtainedby superimposing image data imaged by the imaging sections 12101 to12104, for example.

At least one of the imaging sections 12101 to 12104 may have a functionof obtaining distance information. For example, at least one of theimaging sections 12101 to 12104 may be a stereo camera constituted of aplurality of imaging elements, or may be an imaging element havingpixels for phase difference detection.

For example, the microcomputer 12051 can determine a distance to eachthree-dimensional object within the imaging ranges 12111 to 12114 and atemporal change in the distance (relative speed with respect to thevehicle 12100) on the basis of the distance information obtained fromthe imaging sections 12101 to 12104, and thereby extract, as a precedingvehicle, a nearest three-dimensional object in particular that ispresent on a traveling path of the vehicle 12100 and which travels insubstantially the same direction as the vehicle 12100 at a predeterminedspeed (for example, equal to or more than 0 km/hour). Further, themicrocomputer 12051 can set a following distance to be maintained infront of a preceding vehicle in advance, and perform automatic brakecontrol (including following stop control), automatic accelerationcontrol (including following start control), or the like. It is thuspossible to perform cooperative control intended for automatic drivingthat makes the vehicle travel autonomously without depending on theoperation of the driver or the like.

For example, the microcomputer 12051 can classify three-dimensionalobject data on three-dimensional objects into three-dimensional objectdata of a two-wheeled vehicle, a standard-sized vehicle, a large-sizedvehicle, a pedestrian, a utility pole, and other three-dimensionalobjects on the basis of the distance information obtained from theimaging sections 12101 to 12104, extract the classifiedthree-dimensional object data, and use the extracted three-dimensionalobject data for automatic avoidance of an obstacle. For example, themicrocomputer 12051 identifies obstacles around the vehicle 12100 asobstacles that the driver of the vehicle 12100 can recognize visuallyand obstacles that are difficult for the driver of the vehicle 12100 torecognize visually. Then, the microcomputer 12051 determines a collisionrisk indicating a risk of collision with each obstacle. In a situationin which the collision risk is equal to or higher than a set value andthere is thus a possibility of collision, the microcomputer 12051outputs a warning to the driver via the audio speaker 12061 or thedisplay section 12062, and performs forced deceleration or avoidancesteering via the driving system control unit 12010. The microcomputer12051 can thereby assist in driving to avoid collision.

At least one of the imaging sections 12101 to 12104 may be an infraredcamera that detects infrared rays. The microcomputer 12051 can, forexample, recognize a pedestrian by determining whether or not there is apedestrian in imaged images of the imaging sections 12101 to 12104. Suchrecognition of a pedestrian is, for example, performed by a procedure ofextracting characteristic points in the imaged images of the imagingsections 12101 to 12104 as infrared cameras and a procedure ofdetermining whether or not it is the pedestrian by performing patternmatching processing on a series of characteristic points representingthe contour of the object. When the microcomputer 12051 determines thatthere is a pedestrian in the imaged images of the imaging sections 12101to 12104, and thus recognizes the pedestrian, the sound/image outputsection 12052 controls the display section 12062 so that a squarecontour line for emphasis is displayed so as to be superimposed on therecognized pedestrian. The sound/image output section 12052 may alsocontrol the display section 12062 so that an icon or the likerepresenting the pedestrian is displayed at a desired position.

As described hereinbefore, an example of the vehicle control system towhich the technology according to the present disclosure can be appliedis explained. The technology according to the present disclosure can beapplied to the imaging section 12101 in the configurations explainedhereinbefore. Specifically, the CMOS image sensor 10 in FIG. 1 can beapplied to the imaging section 12031. The technology according to thepresent disclosure is applied to the imaging section 12031, so that, forexample, the pixel property can be improved and generation of residualimages or decrease in the sensor sensitivity can be suppressed to obtaina captured image with higher quality. Hence, obstacles such aspedestrians can be more accurately recognized.

Note that the embodiments of the present technology are not limited tothe embodiments described hereinbefore, and can be variously modifiedwithout departing from the gist of the present technology.

Furthermore, the present technology can have the followingconfigurations.

-   (1)

A solid-state imaging device including:

a first electrode formed on a semiconductor layer;

a photoelectric conversion layer formed on the first electrode;

a second electrode formed on the photoelectric conversion layer; and

a third electrode disposed between the first electrode and an adjacentfirst electrode, and electrically insulated,

in which a voltage of the third electrode is controlled to a voltagecorresponding to a detection result which can contribute to control ofdischarge of charges or assist for transfer of charges.

-   (2)

The solid-state imaging device according to (1), in which the detectionresult includes at least one of detection results regarding a lightamount or a temperature.

-   (3)

The solid-state imaging device according to (1) or (2), in which thevoltage of the third electrode during exposure is feedback-controlledaccording to an output of a frame image obtained before exposure.

-   (4)

The solid-state imaging device according to (3), in which

in a case in which a level corresponding to the output of the frameimage is higher than a predetermined threshold value, the voltage of thethird electrode is decreased to discharge unnecessary charges, and

in a case in which the level corresponding to the output of the frameimage is lower than the predetermined threshold value, the voltage ofthe third electrode is increased to assist the charge transfer.

-   (5)

The solid-state imaging device according to (1) or (2), in which thevoltage of the third electrode during a signal level output isfeedback-controlled according to a reset level output of a pixelincluding the first electrode and the photoelectric conversion layer.

-   (6)

The solid-state imaging device according to (5), in which

in a case in which a level corresponding to the reset level output ishigher than a predetermined threshold value, the voltage of the thirdelectrode during the signal level output is decreased to dischargeunnecessary charges, and

in a case in which the level corresponding to the reset level output islower than the predetermined threshold value, the voltage of the thirdelectrode during the signal level output is increased to assist thecharge transfer.

-   (7)

The solid-state imaging device according to (1) or (2), furtherincluding:

a temperature sensor,

in which the voltage of the third electrode during imaging isfeedback-controlled according to a temperature detection result from thetemperature sensor.

-   (8)

The solid-state imaging device according to (7), in which

in a case in which a level corresponding to the temperature detectionresult is higher than a predetermined threshold value, the voltage ofthe third electrode is decreased to discharge unnecessary charges, and

in a case in which the level corresponding to the temperature detectiontemperature is lower than the predetermined threshold value, the voltageof the third electrode is increased to assist the charge transfer.

-   (9)

The solid-state imaging device according to (1) or (2), in which,according to an output of a light-shielding pixel disposed in a vicinityof a valid pixel including the first electrode and the photoelectricconversion layer, the voltage of the third electrode disposed for thevalid pixel during imaging is feedback-controlled.

-   (10)

The solid-state imaging device according to (9), in which

in a case in which a level corresponding to the output of thelight-shielding pixel is higher than a predetermined threshold value,the voltage of the third electrode of the valid pixel is decreased todischarge unnecessary charges, and

in a case in which the level corresponding to the output of thelight-shielding pixel is lower than the predetermined threshold value,the voltage of the third electrode of the valid pixel is increased toassist the charge transfer.

-   (11)

The solid-state imaging device according to (1) or (2), in which thevoltage of the third electrode during imaging is feedback-controlledaccording to a preset gain.

-   (12)

The solid-state imaging device according to (11), in which

in a case in which a level corresponding to the gain is lower than apredetermined threshold value, the voltage of the third electrode isdecreased to discharge unnecessary charges, and

in a case in which the level corresponding to the gain is higher thanthe predetermined threshold value, the voltage of the third electrode isincreased to assist the charge transfer.

-   (13)

The solid-state imaging device according to any one of (1) to (12), inwhich the first electrode is divided into an accumulation electrode foraccumulating charges, a transfer electrode for transferring charges, anda readout electrode for reading out charges.

-   (14)

The solid-state imaging device according to any one of (1) to (13),further including:

a pixel array section in which pixels each including the first electrodeand the photoelectric conversion layer are two-dimensionally arranged,

in which the third electrode is formed so as to surround the firstelectrode of the pixel in a case in which the third electrode is viewedfrom a light incidence side.

-   (15)

The solid-state imaging device according to (14), in which one or aplurality of the third electrodes is disposed for one pixel.

-   (16)

The solid-state imaging device according to (14), in which the singlethird electrode is disposed for all pixels or a plurality of pixels.

-   (17)

The solid-state imaging device according to (14), in which the voltageof the third electrode is controlled by a one-pixel unit, a plural-pixelunit, or an all-pixel unit.

-   (18)

The solid-state imaging device according to any one of (1) to (17),further including:

a control circuit for controlling the voltage of the third electrode.

-   (19)

The solid-state imaging device according to any one of (1) to (17), inwhich the voltage of the third electrode is controlled by an externalcontrol circuit.

-   (20)

An electronic apparatus mounted with a solid-state imaging device, thesolid-state imaging device including

a first electrode formed on a semiconductor layer,

a photoelectric conversion layer formed on the first electrode,

a second electrode formed on the photoelectric conversion layer, and

a third electrode disposed between the first electrode and an adjacentfirst electrode, and electrically insulated,

in which a voltage of the third electrode is controlled to a voltagecorresponding to a detection result which can contribute to control ofdischarge of charges or assist for transfer of charges.

REFERENCE SIGNS LIST

10 CMOS image sensor, 11 Pixel array section, 12 Vertical drive circuit,13 Column signal processing circuit, 14 Horizontal drive circuit, 15Output circuit, 16 Control circuit, 17 Input/output terminal, 21 Pixeldrive line, 22 Vertical signal line, 23 Horizontal signal line, 30Sensor section, 31 Valid pixel, 32 Light-shielding pixel, 35 Temperaturesensor, 40 CDS circuit, 50 Control circuit, 100 Pixel, 111 Semiconductorlayer, 112 Interlayer insulating layer, 113 Lower electrode, 114, 114-1,114-2 Shield electrode, 115 Photoelectric conversion layer, 116 Upperelectrode, 121 Floating diffusion region, 141 Insulating film, 1000Electronic apparatus, 1001 Solid-state imaging device, 12031 Imagingsection

The invention claimed is:
 1. A solid-state imaging device comprising: afirst electrode on a semiconductor layer, wherein the first electrode isdivided into an accumulation electrode to accumulate charges, a transferelectrode to transfer charges, and a readout electrode to read outcharges; a photoelectric conversion layer on the first electrode; asecond electrode on the photoelectric conversion layer; and a thirdelectrode disposed between the first electrode and an adjacent firstelectrode, and electrically insulated, wherein a voltage of the thirdelectrode is controlled to a voltage corresponding to a detection resultwhich contributes to control of discharge of charges or assist fortransfer of charges, and wherein the voltage of the third electrode isfeedback-controlled based on at least one of: an output of a frame imageobtained before exposure, a reset level output of a pixel that includesthe first electrode and the photoelectric conversion layer, atemperature of the pixel, or an output of a light-shielding pixeldisposed in a vicinity of the pixel that includes the first electrodeand the photoelectric conversion layer.
 2. The solid-state imagingdevice according to claim 1, wherein the detection result includes atleast one of detection results regarding a light amount or thetemperature.
 3. The solid-state imaging device according to claim 1,wherein the voltage of the third electrode during exposure isfeedback-controlled based on the output of the frame image obtainedbefore exposure.
 4. The solid-state imaging device according to claim 3,wherein in a case in which the voltage of the third electrode isfeedback-controlled based on the output of the frame image and a levelthat corresponds to the output of the frame image is higher than apredetermined threshold value, the voltage of the third electrode isdecreased to discharge unnecessary charges, and in a case in which thevoltage of the third electrode is feedback-controlled based on theoutput of the frame image and the level that corresponds to the outputof the frame image is lower than the predetermined threshold value, thevoltage of the third electrode is increased to assist for the transferof charges.
 5. The solid-state imaging device according to claim 1,wherein the voltage of the third electrode during a signal level outputis feedback-controlled based on the reset level output of the pixel thatincludes the first electrode and the photoelectric conversion layer. 6.The solid-state imaging device according to claim 5, wherein in a casein which the voltage of the third electrode is feedback-controlled basedon the reset level output and a level that corresponds to the resetlevel output is higher than a predetermined threshold value, the voltageof the third electrode during the signal level output is decreased todischarge unnecessary charges, and in a case in which the voltage of thethird electrode is feedback-controlled based on the reset level outputand the level that corresponds to the reset level output is lower thanthe predetermined threshold value, the voltage of the third electrodeduring the signal level output is increased to assist for the transferof charges.
 7. The solid-state imaging device according to claim 1,further comprising: a temperature sensor, wherein the voltage of thethird electrode during imaging is feedback-controlled based on atemperature detection result from the temperature sensor.
 8. Thesolid-state imaging device according to claim 7, wherein in a case inwhich the voltage of the third electrode is feedback-controlled based onthe temperature of the pixel and a level that corresponds to thetemperature detection result is higher than a predetermined thresholdvalue, the voltage of the third electrode is decreased to dischargeunnecessary charges, and in a case in which the voltage of the thirdelectrode is feedback-controlled based on the temperature of the pixeland the level that corresponds to the temperature detection result islower than the predetermined threshold value, the voltage of the thirdelectrode is increased to assist for the transfer of charges.
 9. Thesolid-state imaging device according to claim 1, wherein, based on theoutput of the light-shielding pixel disposed in a vicinity of a validpixel that includes the first electrode and the photoelectric conversionlayer, the voltage of the third electrode disposed for the valid pixelduring imaging is feedback-controlled.
 10. The solid-state imagingdevice according to claim 9, wherein in a case in which the voltage ofthe third electrode is feedback-controlled based on the output of thelight-shielding pixel and a level that corresponds to the output of thelight-shielding pixel is higher than a predetermined threshold value,the voltage of the third electrode of the valid pixel is decreased todischarge unnecessary charges, and in a case in which the voltage of thethird electrode is feedback-controlled based on the output of thelight-shielding pixel and the level that corresponds to the output ofthe light-shielding pixel is lower than the predetermined thresholdvalue, the voltage of the third electrode of the valid pixel isincreased to assist for the transfer of charges.
 11. The solid-stateimaging device according to claim 1, wherein the voltage of the thirdelectrode during imaging is feedback-controlled further based on apreset gain.
 12. The solid-state imaging device according to claim 11,wherein in a case in which a level that corresponds to the preset gainis lower than a predetermined threshold value, the voltage of the thirdelectrode is decreased to discharge unnecessary charges, and in a casein which the level that corresponds to the preset gain is higher thanthe predetermined threshold value, the voltage of the third electrode isincreased to assist for the transfer of charges.
 13. The solid-stateimaging device according to claim 1, further comprising: a pixel arraysection in which pixels, each including the first electrode and thephotoelectric conversion layer, are two-dimensionally arranged, whereinthe third electrode surrounds the first electrode of each pixel in acase in which the third electrode is viewed from a light incidence side.14. The solid-state imaging device according to claim 13, wherein one ora plurality of the third electrodes is disposed for one pixel of thepixel array section.
 15. The solid-state imaging device according toclaim 13, wherein the single third electrode is disposed for all pixelsof the pixel array section or a plurality of pixels of the pixel arraysection.
 16. The solid-state imaging device according to claim 13,wherein the voltage of the third electrode is controlled by a one-pixelunit, a plural-pixel unit, or an all-pixel unit.
 17. The solid-stateimaging device according to claim 1, further comprising: a controlcircuit configured to control the voltage of the third electrode. 18.The solid-state imaging device according to claim 1, wherein the voltageof the third electrode is controlled by an external control circuit. 19.An electronic apparatus mounted with a solid-state imaging device, thesolid-state imaging device comprising: a first electrode on asemiconductor layer, wherein the first electrode is divided into anaccumulation electrode to accumulate charges, a transfer electrode totransfer charges, and a readout electrode to read out charges, aphotoelectric conversion layer on the first electrode, a secondelectrode on the photoelectric conversion layer, and a third electrodedisposed between the first electrode and an adjacent first electrode,and electrically insulated, wherein a voltage of the third electrode iscontrolled to a voltage corresponding to a detection result whichcontributes to control of discharge of charges or assist for transfer ofcharges, and wherein the voltage of the third electrode isfeedback-controlled based on at least one of: an output of a frame imageobtained before exposure, a reset level output of a pixel that includesthe first electrode and the photoelectric conversion layer, atemperature of the pixel, or an output of a light-shielding pixeldisposed in a vicinity of the pixel that includes the first electrodeand the photoelectric conversion layer.
 20. A solid-state imaging devicecomprising: a first electrode on a semiconductor layer; a photoelectricconversion layer on the first electrode; a second electrode on thephotoelectric conversion layer; a third electrode disposed between thefirst electrode and an adjacent first electrode, and electricallyinsulated, wherein a voltage of the third electrode isfeedback-controlled based on a detection result to control of dischargeof charges or assist for transfer of charges, and wherein the detectionresult is based on at least one of: an output of a frame image obtainedbefore exposure, a reset level output of a pixel that includes the firstelectrode and the photoelectric conversion layer, a temperature of thepixel, or an output of a light-shielding pixel disposed in a vicinity ofthe pixel that includes the first electrode and the photoelectricconversion layer.